All types of conductors are subject to transient voltages which potentially damage associated unprotected electronic and electrical equipment. Transient incoming voltages can result from lightning, electromagnetic pulses, electrostatic discharges, or inductive power surges.
More particularly, transients must be eliminated from electrical circuits and equipment used in radar, avionics, sonar and broadcast. The need for adequate protection is especially acute for defense, law enforcement, fire protection, and other emergency equipment. A present approach to suppressing transients is to use silicon p-n junction devices. The p-n junction devices are mounted on a substrate, commonly a circuit board. They serve as a dielectric insulator until a voltage surge reaches a sufficient value to generate avalanche multiplication. Upon avalanche multiplication, the transient is shunted through the silicon device to a system ground.
Several problems are associated with this prior art solution and other approaches which analogously use Zener diodes, varistors, and gas discharge tubes.
Many of the foregoing circuits and equipment employ components which are mounted on the surface by soldering leads to the conductors of a printed circuit board or conductors in a hybrid circuit. There is a need for a transient protection device which can be surface mounted.
An ideal transient protection device should have the capability of handling high energy with high response time, in the nanosecond or even sub-nanosecond range.